Redundant Scheduling Functions in Wireless Base Stations
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Solution Overview
Problem
Centralized radio base stations face difficulties in performing flexible scheduling, particularly when faced with non-ideal front-haul conditions, where propagation delays hinder the reflection of latest radio quality in scheduling, and independent cell scheduling limits inter-cell coordination.
Innovation Solution
Implementing redundant scheduling functions in both the Central Unit (CU) and Distributed Unit (DU) of the radio base station, allowing dynamic selection and prioritization of scheduling functions based on front-haul quality, processing load, frequency band, and traffic characteristics to adapt to varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If scheduling function is centralized in CU only, then inter-cell coordination is improved, but scheduling flexibility under non-ideal front-haul conditions deteriorates
Solution Approach 1:
The scheduling function is segmented into two parts: a first scheduling function in the DU for rapid local scheduling decisions, and a second scheduling function in the CU for coordinated multi-cell scheduling. This segmentation allows the DU to perform scheduling independently when front-haul conditions are poor, reducing the impact of propagation delays while maintaining inter-cell coordination capabilities through the CU's scheduling function.
2Speed
If scheduling function is distributed in DU only, then scheduling responsiveness is improved, but inter-cell coordination deteriorates
Solution Approach 1:
The scheduling function is divided between DU and CU, with the DU holding a first scheduling function for immediate local scheduling decisions that ensures responsiveness, and the CU holding a second scheduling function that enables coordinated scheduling across multiple cells. This segmentation allows both rapid local response and coordinated multi-cell operation to coexist.
3Adaptability or versatility
If redundant scheduling functions are implemented in both CU and DU, then scheduling adaptability is improved, but device complexity increases
Solution Approach 1:
The scheduling function is segmented into two instances across DU and CU, where each instance handles specific scheduling tasks appropriate to its location and capabilities. This segmentation provides adaptability by allowing the system to utilize either or both scheduling functions depending on conditions, while the modular segmented architecture actually reduces overall complexity compared to a fully centralized or fully distributed approach.
Data Source
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AI summary
A radio base station includes: a first device that includes a radio unit that performs radio communication with a radio terminal and a first control unit that controls the radio communication; and a second device that is connected to the first device via a network and includes a second control unit that controls the radio communication, wherein a first scheduling function that is at least a part of a scheduling function for the radio communication of the first control unit and a second scheduling function that is at least a part of a scheduling function for the radio communication of the second control unit are redundant.